Thermostatic device



March 19, 1929.

v. E. DUEMLER ET A1. 1,706,057

THERMOSTATIC DEVICE lFiled Jan. 19, 1925 FHLL- Patented Mar. 19, 1929. l I UNiTED STATES 'PATENT oFFicE.

vmeir. n DUEMLER, or mrnnwoon, AND GEORGE n.' xoELN, or sr. Louis, Mrs- BQUBI, ASSIGNORS, B Y MESNE ASSIGNMENTS, T ELECTBDL, INC. 0I' MISSOURI, 0F

BT. LOUIS, MISSOURL-A CORPORATION 0F MISSOURI. i

l 'THEBMOSTATIC DEVICE.

Application led January 19, 1925. Serial No. 3,406.

This invention relates toimprovements in thermostatic devices, and consists in the novel construction hereinafter disclosed.

An object of the invention is to provide a thermostatic device that may be mounted in a heating element and arranged to close a circuit upon a predetermined minimum rise in temperature and to maintain the circuit closed -dur'ing a rise in temperature .10 range, and to open the circuit upon a presection on the line 2-2 2li trated in the drawing the invention is shown as comprising a case 1 having a front. cover 2 and a cylindrical extension 3 running at right angles to the case constituting a housing for the thermostatic element of thev device. Connected with the case 1 and surrounding the extension 3 is a threaded connection 4 adapted to thread into an opening in a wall 5 of the apparatus in which the device is to be mounted such, for instance, as the stack of a heating element or the wall of the combustion chamber of a heating element.

The device may be supportedv in place by jam? nuts 6, operating against opposite sides of the wall 5 against washers 7, said )am nuts being threaded over'the threaded por- \tion of the connector 4.

A bi-metallic thermal plate 8 is connected to the end wall 9 of the casing 3, the plate 8 being connected preferably by a removable connection such as a bolt .10. `The thermal element extends forwardly 4into the case 1, the forward end being free to move laterally under the iniuence of change of temperature surrounding the extension 3 of the case. Extending transversely of the case 1 near the upper rpart thereof is an insulating member including three separated strips of insulating material 11,. 12 and .13 respectively,

`said insulating material being supported by the back wall of the case 1 by spaced bolts 14-passing through openings 15 in the back wall of the case. A bushing 16 serves to space said insulating element from the back wall of the case 1. The bolts 14 carry at their forward ends nuts'17 between which and the forward edge of the bushing 16 are' clamped the three strips of insulating material constituting the insulating element.

On the upper wall of the case 1 is a segmental insulating strip 18 through which the lower stems of binding posts 19 and 20, respectively, extend constituting means for connecting the device with opposite leads of an electric circuit. .l y'

Extending through the strips 11 and 13`,

respectively, in opposite directions and with.

their heads abutting against the separating said bolts being preferably made polygonal and set in recesses formed in their respective retaining strips'so that they will not turn.

A metallic connector plate 23 having an opening near its lower end fits over the s ank of the bolt 21 and has itsface against the face of the strip 11 and extends upwardly, and has ,an over-turned end with an opening therein thatmounts over the lower end of the binding -post 20 to which it is attached by a nut 24.

, A similar connector plate 25 lits over. the bolt 22 and abuts against .the face of the strip 13-and is attached to the lower'end of the binding post 19 by a nut 26. A contact plate 27 having-an openin therein fits over the exterior of an internally threaded shank 28 of a nut 29, said nut 29 threading over strip 12 are bolts 21 and 22, the heads of the end of the bolt 21. The upper part of the plate 27 abuts against the ace of the connector plate 23 and has an inwardly formed bead 30 for effecting contact with the connector plate 23, the contact plate` 27 being held resiliently in contact with said plate 23 by a lspring 31 interposed between and 33, the ear 32 havin .on its inner face an insulating strip 34 an the ear 33 having vtheplate and the head of the nut 29 and formed in connection therewith a contact v member 35.

- abutting against the face ofthe plate 25,

the arrangement for the mounting of the plate 36 being a duplicate of that for the plate 27. The'plate 36 is of greater length than the plate 27 and extends downwardly to the lower part of thecase l having. a

- bifurcated end 40 that fits over the outerv end of the thermostatic element 8 and has inwardly extending ears 41 and 42 in substantial alinement with the ears 32 and 33 of the plate 27.

A U-shaped contact spring 43 is attached at one end to the inner face of the ear 41 and extends exteriorly of the ear '42 and has a contact member 44. 1

The operation of the device isv as follows: Upon a change in temperature suirounding the portion 3 of the case the outer` end of the thermostatic plate Sis deflected laterally, until the contact element 44 makes contact with the Contact element 35. This closes the circuit through the device. A continuedfurther movement of the end of the thermostatic plate moves both contact plates 27 and 36 laterally in the same direction, the.

ear 42 serving as an abutment for the free end of the spring 43 'and the contact elements 44 and 35 remaining in contact. Upon a change in .temperature in reverse degree upon a slight retracting movement of the end of fthe thermostatic plate, the contact between the elements 35 and 44 is immediately broken, opening the circuit. A

further change in temperature in the reverse direction carries both of the contact plates 27 and 36 toward normal osition.

It is obvious therefore that the evice may be used either to effect the making and breaking of the circuit within a .narrow range and under the iniiuence of heat or cold, depending upon the arrangement of the thermostatic plate 8, and' that so long as the change in temperature continues in' one direction the contact will be closed and will remain closed during a substantial range in temperature in the same' direction. Upon a slight reverse change the contact will be immediately' broken and as long as the temperature moves in the reverse direction the circuit will remain open. i We are aware that the -invention may be modified in certain particulars without de.- parting from the spirit and scope thereof. We therefore do not limit ourselves to unessentialdetails, but what we claim and def'- sire to secure by Letters Patent is l. A thermostatic device comprising a case, a thermostatic plate4 supported' rigid with one wall of Isaid case, a pair of pivoted contact elements, means for insulating said 'elements from each other, operative con nections between the free end of said Ythermostatic plate and one of said elements, and

tively, normall other and requiring independent movementA and will break contact between said elements upon a reverse change in temperature within ments pivoted on said support, terminal posts for two wires of a circuit, connector plates between said terminal posts and said conwtact elements respectively, resilient means for maintaining contact between said connectors and the respective contact elements, a thermostatic plate operatively connected with one of said elements, and contact points carried by said contact elements, respecout of contact with each of one of said contact members to eifect contact.

3. In a device of the class described, an insulating support, a air of contact elements pivoted on s ai support, terminal posts for two wires of a circuit, connector plates between said terminal posts and said contact elements respectively, resilient means for maintaining contact between said connectors and the respective contact elements, a' thermostatic, plate operatively connected with one of said elements, contact points carried by said contact elements respectively, normally out of contact lwith each other and requiring independent movement of one of vsaid contact members to eiect contact, and means for effecting an operative connection between said contact elements whereby continued movement iii one direction will move both contact elements to maintain cony tact between said contact points.

4. ln a device of vthe class described, a pivoted contact plate having electrical con-1 nection with one lead of an electric circuit, lears carried-by said plate near its free end, one of said ears being provided with an insulating abutment and the other of said ears being provided with an electrical Contact point, a second contact plate, ears carried by said second contact plate within'the space between the ears of said rst named plate, a contact spring rigidly supported by one of said last named ears, the other of said last named ears -constituting an abutment for the "free end thereof, and-a 4thermostatic plate operatively connected toV said last named contact plate-for moviiigthe same.

5. ln a thermostatic-device, a pair of contact members arranged tor limited independent movement, a heat controiled device for moving one of said members, contact points arranged onV said members respective#V ly 'to effect' electrical Contact when'one of lsaid member is moved in one direction and to break contact when said member is moved in the opposite direction, and an insulated. 4abutment for insulating said elements lwhen moved in the` opposite direction.

' 6. In a thermostatic device, a pair of contact members arranged for limited independent movement, a thermostatic plate for Amoving one of said members, a resilient connection lfor making electrical contact when one member is moved in one direction and to break contact when said member is moved in the opposite direction, a connection between the air of contact members whereby one of sai members is moved in one direction by the other member without making electrical contact, and means for connecting said contact members -with separate leads of I a circlt respectively.

7. In a thermostatic device, a pair of contact members arranged for limited independent movement, a fiat elongated thermostatic plate having one end fixed and the other end engaging one of said members to move the same, a connection for making electric Contact when one member is moved in one direction and to break contact when said member is moved in the opposite direction, an insulated connection between the contact members, and means for connecting said contact members with separate leads of a circuit respectively.

VIRGIL E. DUEMLER. GEORGE R. KOELN. 

